Radioactive Contaminants

Radioactive Contaminants are a source of Polluted Dirt associated with radioactive worlds and space exploration. On the Radioactive Ocean Asteroid and the Flipped Asteroid, early colony setup is constrained because neither provides a source of Reed Fiber, which delays Atmo Suit production and makes Oxygen Masks the usual stopgap for the first landing attempts.

Polluted Dirt appears in several production chains and resource loops. Outhouses convert Dirt into Polluted Dirt with a net gain in mass, the Ethanol Distiller produces it as a by-product of Lumber processing, and the Water Sieve creates a small amount when cleaning Polluted Water. Pacus and their variants also consume Algae and excrete Polluted Dirt, while rocket missions can harvest large amounts from renewable space points of interest, especially Swampy Ore Fields. The Sludge Press can also turn Polluted Mud into Polluted Dirt and Polluted Water, with output depending on the operator’s Machinery skill.

Once available, Polluted Dirt is useful in a number of basic colony systems. It can be turned back into Dirt in a Compost, fed to Sage Hatches for Coal, fed to Pokeshells for Sand, or processed in a Sublimation Station to generate Polluted Oxygen. Because of that, it serves both as a waste product and as a feedstock for secondary production.

Its main hazard is gas off-gassing. If stored below 1800 g of pressure, Polluted Dirt emits Polluted Oxygen over time and gradually loses mass, even when placed inside Storage Bins. The emission rate depends on the exposed perimeter, or equivalently the square root of the stored mass: rate = 0.2 × sqrt(mass) in the base game. In Spaced Out, the rate is reduced by a factor of 10 to 0.02 × sqrt(mass). This behavior is intentional, since some asteroids can contain very large deposits that would otherwise flood nearby rooms with gas very quickly.

The emission can be prevented by keeping Polluted Dirt submerged in a liquid or by storing it under at least 1.8 kg/tile of gas pressure. That makes it easy to quarantine large stockpiles until they are needed for farming, composting, or oxygen production. If left exposed, however, it will steadily become an oxygen source and a contamination problem at the same time.

Guaranteed geysers on the related world set include Carbon Dioxide Geyser and Salt Water Geyser, and additional geysers such as Cool Salt Slush Geyser, Polluted Water Vent, Steam Vent, and Infectious Polluted Oxygen Vent may also appear.